THEORY AND EXPERIMENT FOR THE XUV EFFICIENCY OF A 1000-LINES MM HOLOGRAPHIC GRATING/

Diffraction efficiencies of a laminar grating measured in the soft X-r ay region with photon energies between 30 eV and 800 eV are compared w ith calculations using the Differential Formalism of the exact electro magnetic theory and with calculations using a model based on making a reasonable assumption for the electric field in the bars of the gratin g and applying the Ewald-Oseen theorem. The grating profile is charact erized by STM measurements, and the optical constants of the material are determined separately. Rotating sample and detector according to t he grating equation provides continuous efficiency curves for the diff erent diffraction orders at selected photon energies.